ACGIH

American Conference of Governmental Industrial Hygienists.

ASHRAE

American Society of Heating, Regrigerating, and Air-Conditioning Engineers.

ASTM

American Society for Testing and Materials.

ACTION LEVEL

A term used to identify the level of indoor radon at which remedial action is recommended.

ACTION PACKET

In reference to the indoor air quality Tools for Schools Kit. The packet contains three components - an introductory memo, IAQ Backgrounder, and IAQ Checklist - to assist school personnel to implement an effective yet simple indoor air quality program in their school.

AHU

This is the abbreviated form used for the term "Air Handling Unit" which is described below.

AIR CLEANING

An indoor air quality control strategy to remove various airborne particulates and/or gases from the air. The three types of air cleaning most commonly used are particulate filtration, electrostatic precipitation, and gas sorption.

AIR EXCHANGE RATE

The rate at which outside air replaces indoor air in a space. Expressed in one of two ways: the number of changes of outside air per unit of time in air changes per hour (ACH); or the rate at which a volume of outside air enters per unit of time - cubic feet per minute (cfm).

AIR HANDLING UNIT (AHU)

This refers to equipment used to provide conditioned air to a space. The air handler unit generally includes a blower or fan, heating and/or cooling coils, and related equipment such as controls, condensate drain pans, and air filters. Does not include ductwork, registers or grilles, or boilers and chillers.

ALLERGENS AND PATHOGENS

Biological material, including bacteria, viruses, fungi, mold spores, pollens, skin flakes and insect parts are ubiquitous in indoor environments. These particulates range from less than one to several microns in size. When airborne, they are usually attached to dust particulates of various sizes so that all sizes of airborne particulates may include them.

ANTIMICROBIAL

Agent that kills microbial growth.

APR

Air Purifying Respirator

BIOCIDE

Substance or chemicals that kills organisms such as molds.

BIOLOGICAL CONTAMINANTS

Agents derived from, or that are, living organisms (e.g., viruses, bacteria, fungi, and mammal and bird antigens) that can be inhaled and can cause many types of health effects including allergic reactions, respiratory disorders, hypersensitivity diseases, and infectious diseases. Also referred to as "microbiologicals" or "microbials."

BREATHING ZONE

That area of a room in which occupants breathe as they stand, sit, or lie down.

BUILDING ENVELOPE

Elements of the building, including all external building materials, windows, and walls, that enclose the internal space.

BUILDING-RELATED ILLNESS (BRI)

Diagnosable illness whose symptoms can be identified and whose cause can be directly attributed to airborne building pollutants (e.g., Legionnaire's disease, hypersensitivity pneumonitis). Also: A discrete, identifiable disease or illness that can be traced to a specific pollutant or source within a building. (Contrast with "Sick building syndrome").

CEILING PLENUM

Space located above the suspended ceiling that accomodates the mechanical and electrical equipment and that is used as part of the air distribution system. The space is kept under negative pressure.

CENTRAL AIR HANDLING UNIT (Central AHU)

This is the same as an Air Handling Unit, but serves more than one area.

CFM Cubic feet per minute

The amount of air, in cubic feet, that flows through a given space in one minute.

CHEMICAL SENSITIZATION

Evidence suggests that some people may develop health problems characterized by effects such as dizziness, eye and throat irritation, chest tightness, and nasal congestion that appear whenever they are exposed to certain chemicals. People may react to even trace amounts of chemicals to which they have become "sensitized."

CO Carbon monoxide

Carbon monoxide is an odorless, colorless, and tasteless gas. It results from incomplete oxidation of carbon in combustion.

CO2 Carbon dioxide

Carbon dioxide is a colorless, odorless, and tasteless product of completed combustion. Sources of this include all combustion processes and the human metabolic process. CO2 is also found in ambient atmosphere.

COMMISSIONING

Start-up of a building that includes testing and adjusting HVAC, electrical, plumbing, and other systems to assure proper functioning and adherence to design criteria. Commissioning also includes the instruction of building representatives in the use of the building systems.

CONDITIONED AIR

Air that has been heated, cooled, humidified, or dehumidified to maintain an interior space within a carefully defined "comfort zone."

CONSTANT AIR VOLUME SYSTEMS

Air handling system that provides a constant air flow while varying the temperature to meet heating and cooling needs.

DAMPERS

Controls that vary airflow through an air outlet, inlet, or duct. A damper position may be immovable, manually adjustable or part of an automated control system.

DIFFUSERS AND GRILLES

Components of the ventilation system that distribute and return air to promote air circulation in the occupied space. Generally speaking, supply air enters a space through a diffuser or vent and return air leaves a space through a grille.

DRAIN TRAP

A dip in the drain pipe of sinks, toilets, floor drains, etc., which is designed to stay filled with water, thereby preventing sewer gases from escaping into the room.

DUST

Dust is comprised of particles in the air that settle on surfaces. Large particles settle quickly and can be trapped by the body's defense mechanisms. Small particles are more likely to be airborne and are capable of passing through the body's defenses and entering the lungs.

ENVIRONMENTAL AGENTS

Conditions other than indoor air contaminants that cause stress, comfort, and/or health problems (e.g., humidity extremes, drafts, lack of air circulation, noise, and over-crowding).

ENVIRONMENTAL TOBACCO SMOKE (ETS)

Mixture of smoke from the burning end of a cigarette, pipe, or cigar and smoke exhaled by the smoker.

EPA

Environmental Protection Agency

ERGONOMICS

The science that investigates the impact of people's physical environment on their health and comfort (e.g., chair design, monitor location, desk configuration or height, etc.)

EXHAUST VENTILATION

Mechanical removal of air from a portion of a building (e.g., piece of equipment, room, or general area).

FLOW HOOD

Device that easily measures airflow quantity, typically up to 2,500 cfm.

FORMALDEHYDE

Formaldehyde is a colorless water-soluble gas. Due to its wide use, it is frequently considered separately from other volatile organic compounds (VOCs)

FUNGI

Any of a group of parasitic lower plants that lack chlorophyll, including molds and mildews.

FUNGICIDE

Substance or chemical that kills fungi.

GAS SORPTION

Devices used to reduce levels of airborne gaseous compounds by passing the air through materials that extract the gases.

HEPA

High efficiency particulate arrestance (filters).

HVAC

Heating, ventilation, and air-conditioning system.

HYPERSENSITIVITY DISEASES

Diseases characterized by allergic responses to pollutants. The hypersensitivity diseases most clearly associated with indoor air quality are asthma, rhinitis, and hypersensitivity pneumonitis.

HYPERSENSITIVITY PNEUMONITIS

A group of respiratory diseases that cause inflammation of the lung. Most forms of hypersensitivity pneumonitis are caused by the inhalation of organic dusts, including molds.

IAQ

Indoor air quality.

IAQ BACKGROUNDER

A component of the IAQ Tools for Schools Action Packet that provides a general introduction to IAQ issues in educational facilities.

IAQ COORDINATOR

An individual (usually with facility management) who provides leadership and coordination of all IAQ activities.

IAQ MANAGEMENT PLAN

A set of flexible and specific steps for preventing and resolving IAQ problems in any kind of commercial facility.

IPM

Integrated pest management.

INDICATOR COMPOUNDS

Chemical compounds, such as carbon dioxide, whose presence at certain concentrations may be used to estimate certain building conditions (e.g., airflow, presence of sources).

INDOOR AIR POLLUTANT

Particles and dust, fibers, mists, bioaerosols, and gases or vapors.

MAKE-UP AIR

See "Outdoor Air Supply."

MICROBIOLOGICALS

See "Biological Contaminants."

MOLD

Molds are a group of organisms that belong to the kingdom Fungi. In this document, the terms fungi and mold are used interchangeably. There are over 20,000 species of mold.

MULTIPLE CHEMICAL SENSITIVITY (MCS)

A condition in which a person reports sensitivity or intolerance (as distinct from "allergic") to a number of chemicals and other irritants at very low concentrations.

mVOC

Microbial volatile organic compound, a chemical made by a mold which may have a moldy or musty odor.

NEGATIVE PRESSURE

Condition that exists when less air is supplied to a space than is exhausted from the space, so the air pressure within that space is less than that in surrounding areas. Under this condition, if an opening exists, air will flow from surrounding areas into the negatively pressurized space.

NITROGEN DIOXIDE

The two most prevalent oxides of nitrogen are nitrogen dioxide (NO2) and nitric oxide (NO). Both are toxic gases with NO2 being a highly reactive oxidant, and corrosive. NO gradually reacts with the oxygen in the air to form NO2.

ORGANIC COMPOUNDS

Chemicals that contain carbon. Volatile organic compounds vaporize at room temperature and pressure. They are found in many indoor sources, including many common household products and building materials.

OSHA

Occupational Safety and Health Administration

OUTDOOR AIR SUPPLY

Air brought into a building from the outdoors (often through the ventilation system) that has not been previously circulated through the system. Also known as "Make-Up Air."

PAPR

Powered air purifying respirator.

PELs

Permissible Exposure Limits (standards set by the Occupational, Saftey and Health Administration).

PLENUM

Air compartment connected to a duct or ducts.

PM

See "Preventive Maintenance."

POLLUTANT PATHWAYS

Avenues for distribution of pollutants in a building. HVAC systems are the primary pathways in most buildings; however all building components interact to affect how air movement distributes pollutants.

PESTICIDES

Pesticides are chemicals that are used to kill or control pests which include bacteria, fungi, weeds, and other organisms, in addition to insects and rodents. Most pesticides are inherently toxic. Most contain volatile organic compounds.

POSITIVE PRESSURE

Condition that exists when more air is supplied to a space than is exhausted, so the air pressure within that space is greater than that in surrounding areas. Under this condition, if an opening exists, air will flow from the positively pressurized space, outward to surrounding areas.

PPE

Personal Protective Equipment

PPM

Parts per million.

PRESSED WOOD PRODUCTS

A group of materials used in building and furniture construction that are made from wood veneers, particles, or fibers bonded together with an adhesive under heat and pressure.

PREVENTIVE MAINTENANCE

Primarily done on a building's mechanical systems, this involves a regular and systematic inspection, cleaning, and replacement of worn parts, materials, and systems. Preventive maintenance helps to prevent parts, material, and systems failure by ensuring that parts, materials and systems are in good working order.

PSYCHOSOCIAL FACTORS

Psychological, organizational, and personal stressors that could produce symptoms similar to those caused by poor indoor air quality.

RADON (Rn) and RADON DECAY PRODUCTS

Radon is a radioactive gas formed in the decay of uranium. The radon decay products (also called radon daughters or progeny) can be breathed into the lung where they continue to release radiation as they further decay.

RE-ENTRAINMENT

Situation that occurs when the air being exhausted from a building is immediately brought back into the system through the air intake and other openings in the building envelope.

RELs

Recommended Exposure Limits (recommendations made by the National Institute for Occupational Safety and Health (NIOSH)).

REMEDIATE

Fix

SENSITIZATION

Repeated or single exposure to an allergen that results in the exposed individual becoming hypersensitive to the allergen.

SHORT-CIRCUITING

Situation that occurs when the supply air flows to return or exhaust grilles before entering the breathing zone (area of a room where people are). To avoid short-circuiting, the supply air must be delivered at a temperature and velocity that results in mixing throughout the space.

SICK BUILDING SYNDROME (SBS)

Term that refers to a set of symptoms that affect some number of building occupants during the time they spend in the building and diminish or go away altogether during periods when they leave the building. (Contrast with Building Related Illness.)

SOURCES

Sources of indoor air pollutants. Indoor air pollutants can originate within the building or be drawn in from outdoors. Common sources include people, fixtures and furnishings, photocopiers, plants, food, etc.

SPORE

Molds reproduce by means of spores. Spores are microscopic; they vary in shape and size (2-100 micrometers). Spores may travel in several ways--they may be passively moved (by a breeze or waterdrop), mechanically disturbed (by a person or animal passing by), or actively discharged by the mold (usually under moist conditions or high humidity).

STACK EFFECT

The overall upward movement of air inside a building that results from heated air rising and escaping through openings in the building super structure, thus causing an indoor pressure level lower than that in the soil gas beneath or surrounding the building foundation.

STATIC PRESSURE

Condition that exists when an equal amount of air is supplied to and exhausted from a space. At static pressure, equilibrium has been reached.

TRACER GASES

Compounds, such as sulfur hexaflouride, which are used to identify suspected pollutant pathways and to quantify ventilation rates. Trace gases may be detected qualitivatively by their odor or quantitatively by air monitoring equipment.

TLVs

Threshold Limit Values (guidelines recommended by the American Conference of Governmental Industrial Hygenists).

TVOCs

Total volatile organic compounds. See "Volatile Organic Compounds (VOCs)"

VENTILATION AIR

Defined as the total air, which is a combination of the air brought inside from outdoors and the air that is being recirculated within the building.

VENTILATION RATE

The rate at which indoor air enters and leaves a building. Expressed in one of two ways: the number of changes of outdoor air per unit of time (air changes per hour, or "ach") or the rate at which a volume of outdoor air enters per unit of time (cubic feet per minute, or "cfm").

VOLATILE ORGANIC COMPOUNDS (VOCs)

Compounds that vaporize (become a gas) at room temperature. Common sources which may emit VOCs into indoor air include housekeeping and maintenance products, and building and furnishing materials. In sufficient quantities, VOCs can cause eye, nose, and throat irritations, headaches, dizziness, visual disorders, memory impairment; some are known to cause cancer in animals; some are suspected of causing, or are known to cause, cancer in humans.